Various types of dispensers are disclosed in the prior art. U.S. Pat. Nos. 7,748,579, 5,495,962, 5,772,086 and 6,283,339 disclose particulate dispensers. These dispensers are not appropriate for dispensing liquids because they lack proper seals to prevent potentially harmful liquid chemicals from leaking from the dispenser, but may have some relevance.
U.S. Pat. No. 6,283,339 issued to Morrow discloses a dispenser for use with particulate. Referring to FIG. 5 of the Morrow patent, attached as FIG. 1 to this application, Morrow discloses a twist bottom two-part dispenser 30 and 22 for attachment to the bottom of a cylindrical container 12 holding a powdered or granular product. Open-faced chambered member 30 forms two or more chambers of different volume is contained inside open-faced cup-shaped member 20 and physically attached thereto. Disk 50 closes off the bottom of the chambered member. The particle product is contained inside container 12.
When a user twists the chambered member with respect to the cup-shaped member to cause inlet holes 34 and 35 in the top face of chambered member 30 to align with inlet holes 24 and 25 in cup-shaped member 20, the particle product will flow by means of gravity from the container 12 into both of the chambers formed in the chambered member. When the chambered member 30 is then twisted again by the user with respect to the cup-shaped member so that outlet hole 36 or 37 formed in the side wall of chambered member 30 aligns with outlet hole 26 formed in the side wall of cup-shaped member 20, then the particle product can be discharged from the chamber associated with that outlet hole 36 or 37. The volume of the chamber represents a measured dose of the particle product.
Other prior art dispensers claim to be useful for particulate and liquid. U.S. Pat. No. 6,550,640 issued to Smith is one such patent. As shown in FIG. 6 of the Smith patent (FIG. 2 of this Application), the Smith Patent is directed to a container top for dispensing powered and liquid product like a spice from a spice container. The container top contains a metering drum 22 having three chambers 34, 36, and 38 of different volumes. A proximal control disk 23 is attached to one end of the metering drum having three openings 35 that correspond to the chambers. A distal control disk 43 with an opening is affixed to the bottom of control spout 26. The assembly is screwed into engagement with the top of a spice container.
In operation, the user turns the metering drum with respect to the container in the upright position until the hole in the proximal control disk aligns with a hole in the cap 24 of the container. Upon inverting the container, the spice powder flows from the container into the preselected chamber of the metering drum until its volume is filled to produce a measured dose of the spice. The metering drum is then twisted back to a blank position on the proximal control disk. If the top is twisted until the hole in the distal control disk aligns with the chamber filled with the spice, the spice will flow out of the chamber and through the spout 26 for use.
U.S. Pat. Nos. 5,823,401 and 8,517,228 are examples of dispensers that may be used to dispense either liquid or particulate.
A product sold by Applicant under the trademark SurFlex™ is another example of a liquid dispenser. The SurFlex™ dispenser utilizes multiple valves to control the flow of liquid between a liquid container and various vertically aligned chambers. Multiple seal discs are mounted on a single stem to mate with corresponding seal rings. When the stem is vertically raised, at least one valve opens to allow fluid to flow from the raised liquid container into a reservoir positioned below; when the stem is moved downward, the open valve closes and at least one previously closed valve opens to prevent fluid flow from the container while permitting fluid to be dispensed from the reservoir. However, the SurFlex™ dispenser has some shortcomings in that it fails to provide adequate air flow through the system as fluid flows from the container, through and out the reservoir. Such fluid flow creates a vacuum effect and without sufficient air to take the place of the fluid, it causes the Surflex™ system to dispense fluid slower than desired.
Other than the Surflex™ system, none of the systems referenced above provide an adequate system for dispensing liquid chemical, which can be hazardous to the touch. Thus, there remains a need for a liquid dispenser, and liquid chemical dispenser in particular, that is safe to use and can easily and repeatedly provide measured quantities of liquid chemical quickly on demand.